Di2 Battery Holder for 25.4 mm Seat Posts


3 items left

This battery holder is for Shimano Di2 internal SM-BTR2 and BT-DN110 batteries. The battery fits inside the seat post and typically requires a seat post made specifically for Di2. This holder allows the battery to be held securely within a non-Di2 specific 25.4mm seat post found on many bikes from 2014 to present. It will also fit other seat posts with the same inside diameter.

Collections: Di2-eTAP Conversion Accessories

Why use a holder instead of tape or foam?

Ad hoc solutions using tape and foam have multiple issues. The net result is often a damaged or stuck battery.

Problems with Tape or Foam:

  • They don't protect the delicate battery connection
  • Tape or foam can shrink, causing the battery to fall out
  • They can cause the battery to overheat
  • Tape, especially, can fuse to the inside of the seat post

Battery Holder Sizes

We make Di2 battery holders for 25.4mm seat posts with various inside diameter size options.  If your measurement is close, pick the smaller size.  If the measurement is more than .5 mm from the available sizes, or an odd shape, contact us for a custom version.  There are also versions made for 27.2 mm seat posts.

Typical Seat Post Sizes:

Cannondale Branded

C2 - 19 mm ID

C3 - 19.5 mm ID

FSA Branded

SL-K - 20 mm ID

Aero or Tapered Seat Posts

Some seat posts are tapered on the inside, so if your seat post opening is bigger than 22 mm, check that it doesn't narrow further inside.  We can make customized versions if you have a tapered seat post.  If you have an aero seatpost, we can make versions to accomodate them as well, if we can get proper specifications.  Use the Contact Us form to send a request for a custom holder.

Related Items